Demon and a monster
by Internet scum
Summary: Nothings what it seems, right? So Izaya's new look doesn't mean he's a demon, right? Shizaya, rating is M for language right now but I have plans on making it M for yaoi fantasies later. Summaries are hard! Story's better than summery.
1. Chapter 1

**A.N: This story is based off of the anime but very loosely. It's been a while since I watched the animes for these two but the story has nothing to do with those. This story also contains Shizaya because why not. I also wouldn't really label this a crossover because it only involves Blue Exorcist in the first chapter. Also just a heads up I'm a really shitty writer.**

It was a normal day in Ikebukuro, the sun was shining, birds were chirping and two men were currently trying to kill each other. They chased each other all through Ikebukuro until one was cornered in an ally, "Sigh. Shizu-chan I'm so bored."

"No problem, flea! I'll just kill you!" Izaya shook his head, "No, no. Dying would be boring too. You know you used to be so unpredictable. I was going to stay until I had all information on you but, you're not very fun anymore… I guess it's time for me to go home then. I mean my little brother realised a little something about himself, I should visit him even though it's been a year."

"Listen I know you don't have a brother! You just have those irritating sisters!"

"Tsk. Simple minded as ever. Mairu and Kururi aren't my siblings, they're just to people convinced they are."

"Bullshit!"

"Don't scream what you are Shizu-chan. I'm leaving now so chill, kay?" Izaya smirked at Shizuo as he reached a hand out, "Un, deux, trois!" He snapped his fingers and a gate appeared. "What the fuck is that, Izaya?" Shizuo asked, to confused with the scene in front of him to be as pissed as before. "Really wanna know? Ask Celty about Gehenna and tell her Izaya told you to ask." Izaya laughed as he jumped in the gate. Shizuo reached a hand out to yank Izaya back but the gate slammed shut before Shizuo could even look inside. "IZAYA!" Shizuo stormed off until he was at Shinra's apartment. It took Shinra almost a minute before he answered the door, "Oh, hi Shizuo."

"Hey. Is Celty here?" Shinra nodded, "Come on in." Shinra lead Shizuo inside the house where he told him to wait on the couch. He sat there for another minute or so before Celty walked in, " _Hey Shizuo. What's up?_ "

"Izaya. Bastard fucking disappeared into some gate then said if I wanted to know that I had to ask you about Gehenna gate." Celty's shoulders visibly tensed, " _Izaya… Gehenna. Shizuo, there are things beyond this world out there. Izaya was one of them._ "

"Huh?" Shizuo re-read her PDA, "So you expect me to believe Izaya was some demon or something?"

" _Yeah. I have no reason to lie to you, Shizuo. Besides he isn't just a demon try Satan's third youngest son. He has seven children total his youngest two are only half demon but his second youngest has no traits of a demon at all since the last two were twins… It's hard to explain. Just be glad the demon's gone, he's the real monster Shizuo. I feel bad for wherever he went._ "

 **Assiah**

A man walked through town, his very look made the average human get the chills. Surely this man was human but his nails were long and black, his skin white, his eyes red, and his ears were pointed. "So you're finally back, brother." The man walking stopped and turned on his heel, "It's only been 23 years. Miss me that much… Mephisto Pheles." The chairman of True Cross Academy laughed, "Of course, Izaya. 23 years is a fourth or so of human life."

"And when you live forever?"

"I guess it's not really important. So did you finally get bored of the human world?" Izaya laughed and spun on his heel to face his older brother, "I've been bored of it for a while, the one person who kept me there finally got boring and you should know what I do when I'm bored." Izaya got his switchblade out but before he could open the blade Mephisto Pheles set his hand on Izaya's, "Don't take your boredom out here, in fact our brother may interest you."

"I assume you're talking about Rin. Humans bore me and I'm sick of my other brothers."

"I assure you Rin's something else." Izaya laughed and put away his blade, "Fine." Izaya tapped his foot and looked around suspiciously, "How are the exorcist now a days?"

"I'm sure you can handle them. Oh and if you want to start something with him steal that katana of his. It holds his powers."

"Like my switchblade?"

"I guess. It holds his powers though you just do it for the hell of it, right?" Izaya smirked and did a slight nod, "Good to see you still remember me well. Now to bug Rin~"

Rin was sitting on the roof of True Cross, just enjoying the Sun… "So you're Rin?" He opened his eyes he hadn't even realised were closed until he heard the unfamiliar voice. "Who are you?"

"I'm Izaya Orihara. An older brother of yours… You are Satan's son right? Anyways I'll assume you're a demon since you've got a tail and pointy ears. Oh! You also have the sword I was told about. So Rin…" Izaya smiled at Rin who now stood up, "I wanna see your flames."

"No."

"Come on I'll show you mine." Rin glared at Izaya, "Fine. You first." Izaya nodded and whipped out a switchblade. His smirk never faded as it flung open and his body was wrapped in what looked like normal flames, not blue. "Those aren't Satan's flames."

"I'm sorry, when did the Demon, who may I remind you only knew about demons for a year, become a genius about demons?" Rin opened his mouth to speak only to be cut off, "Never. Anyways I've been in a… different area as of late and haven't seen a real demon for a long while, I've evolved from running… I mean fighting a certain someone. My flames are red and I've got a real fighting technique unlike your random attack style which I can predict thanks to Shizu-chan… No one you know."

"Do you ever shut up?" Izaya shut his blade and smiled evilly at Rin. "Little boy, I'm an ancient demon who was an information broker in Ikebukuro and Shinjuku for 9 years. I say everything important and everything irrelevant will never be mentioned until I and no one else feels the need to say it." Izaya walked closer to Rin, "So are you going to hold up your half of the deal?" Rin made to movements besides walking back the same distance Izaya walked forward. Than for a fraction of a second Izaya's smirk grew and his hand flinched, by time Rin realised what happened he felt something slip from his shoulders. He looked down and seen only the black strap the connected his Katana's bag… His vision snapped back to Izaya to see him holding the bag, "Give that back!"

"Oh?" Izaya removed the red bag and threw it at Rin, "Don't know what you'll do with it now though… You can also take this." He removed the swords sheath and threw the sword at Rin. Rin just looked at Izaya half shocked the other half pissed. "What? I can't fight you if you don't have your sword. Especially if I use mine!" Izaya looked around uneasily for a second, "But let's not fight here… Follow me." Izaya jumped off the roof and ran towards the forest, Rin chasing him. ' _Still not as fun as with Shizu-chan. Nothing's even being thrown at me._ ' Once they were deep enough in the forest Izaya turned around suddenly and went to slice through Rin's chest like he did when he first met Shizuo. He moved though, "So you at least know how to dodge. That means I don't have to go easy on you!" Izaya's body lite on fire too, "Alright Rin, I've itching for a fight that actually hurts for 23 years! Come at me!"

 **Ikebukuro**

" _Are you serious!?_ "

"Yeah. That flea isn't getting away! So can you do it?" Celty put her fingers to her PDA and hesitantly typed, " _Yeah I can send you to where Izaya is… I can't get you back though. This is our chance to never see Izaya again since we all hate him, we like you though so-_ " Shizuo looked away after that, "Listen, I'm also a monster so they're be no issue. Two monsters gone in one day." Celty nodded her helmet, " _Alright Shizuo. I really don't want to though. Before I send you, you need to know I'm not opening a gate but sending you wherever Izaya is… If he's in Gehenna now you'd die._ " Shizuo shrugged, "I'll be fine Celty." Celty stood up and did exactly what Shizuo asked… "Send me to Izaya."

 **Assiah**

The two demons fought, the one laughing like a maniac the other shouting before his every attack. "Rin, screaming makes your attacks awfully easy to detect it's almost… laughable?" Izaya said the last word sincerely but it was what he was seeing behind Rin that made him sound questionable. "Shizuo!?"

"Flea!" Izaya held his blade tighter, "How the Hell'd you get here?"

"Celty. Now, what the Hell did you do to your look?! Oh and I have more questions for you!" Izaya rolled his eyes, "Can it wait? I'm kinda testing out my younger brother… well half brother, we have a different mother." Shizuo looked at the two of them closer, "Why are you two on fire and what's with the tails?"

"Oh my God, Shizuo!" He turned to Rin and threw him his sheath, "Go do something else kid." Izaya turned back to Shizuo, not even caring if he was still there to listen, "These are Satan's flames, idiot! And the tails are just there okay!? You don't need to know anything else about them-"

"Actually a demon's tail is it's weakness."

"Rin, you moron!" He was about to kill Rin if he was pulled back by his tail, "Ow! Shizuo! Let me kill that bastard!" Shizuo laughed which made Izaya, for once in his life, confused. "What's so funny?"

"You're actually angry. I don't think I've ever seen you this way." Izaya's fire simmered, he'd normally ask how he could stand his fire but it was Shizuo. "Well yeah, in case Celty forgot to tell you, I'm one of Satan's children."

"Alright, fine. I just have one question for you now, why'd you leave? I mean I thought-" Izaya looked away, "Shizuo… I mean… that's why I left. Just look at me."

"Are you fucking serious!? I don't care if you're a demon!"

"I do! You'll die, Shizuo, and I won't unless an exorcist kills me! I left so I could forget about you, you idiot!" Izaya did a turn around to run away but came face to face with a man dressed as an… exorcist! Izaya ran behind Shizuo, "Shizuo's a human, you wouldn't hurt him."

"Oi, flea what's your problem?!"

"Exorcists Shizuo! That man is my problem because he's an exorcist!"

"Then I'll kick his ass for you." Shizuo ran at the exorcists, the exorcist made no moves to hurt Shizuo unlike Shizuo who was focused on at least knocking this guy out. "Listen he's a demon, sir. He isn't allowed to live in Assiah unless special permission is granted."

"Listen, exorcist. I'm not gonna hurt anyone I like humans too much to do that." The exorcist loaded a gun and pointed it at Izaya, "Then why'd you attack my brother?"

"Wait, you're Yukio? You look nothing like Rin, aren't you twins?" He never lowered the gun even as he evaded Shizuo's attacks. "How do you know about us?" Izaya sighed, "Shizuo stop." Shizuo stopped attacking and went back to block Izaya. "I'm a brother of yours. I'm Satan's third youngest son. Let's say I wasn't trying to kill Rin, I was just curious to know how strong he was. I did the same thing with Shizuo here when I first met him."

"It's still my job to get rid of you."

"Harsh. Your own brother too, I'd hate to see how you treated Rin. You probably also pointed a gun at him." Yukio flinched for a minute, "Oh my God, you did too! I thought my fake siblings back in Ikebukuro were bad! Anyways this leads to my next move…" He grabbed Shizuo's hand and ran, "Hey Shizuo, this was fun but I think I actually like Ikebukuro better."

"Huh?"

"I'm saying we should he'd back. I mean sure I have no one there since you probably hate me know but you've got your friends and your brother."

"I don't hate you, you flea. You piss me off really easy and yeah I'm really pissed that you left me but once you explained why… I mean that very small journey actually explains a lot about you." They both laughed as they ran still trying to get away from Yukio, "But Izaya."

"What?"

"If you call me monster still I'll start calling you demon."

"Haha, fair enough Shizu-chan… Here!" He yanked Shizuo down an alley, Yukio running past it. "Brings back memories, huh Shizu-chan?" Shizuo laughed and nodded, "Un, deux, trois!" The snapped his fingers and a gate opened, "After you, monster~"

"Same time, demon." Izaya rolled his eyes as Shizuo grabbed his hand and they walked the gate.

 **A.N: Well that was chapter 1, review if you want more. I don't have a real direction for this story so let me know if you want real Shizaya and not the shit I wrote before, more blue exorcist, or if I suck and shouldn't post new stories. I also know Izaya was a little out of character in Assiah but that's because Satan's presence is more 'there' and it just made him more evil… I have no excuse for Shizuo, I just need to try harder. If this gets popular I'll try to post every week! So long~**


	2. Help!

A.N: This story is based off of the anime but very loosely. It's been a while since I watched the animes for these two but the story has nothing to do with those. This story also contains Shizaya because why not. I also wouldn't really label this a crossover because it only involves Blue Exorcist in the first chapter. Also just a heads up I'm a really shitty writer.

It was a normal day in Ikebukuro, the sun was shining, birds were chirping and two men were currently trying to kill each other. They chased each other all through Ikebukuro until one was cornered in an ally, "Sigh. Shizu-chan I'm so bored." "No problem, flea! I'll just kill you!" Izaya shook his head, "No, no. Dying would be boring too. You know you used to be so unpredictable. I was going to stay until I had all information on you but, you're not very fun anymore… I guess it's time for me to go home then. I mean my little brother realised a little something about himself, I should visit him even though it's been a year." "Listen I know you don't have a brother! You just have those irritating sisters!" "Tsk. Simple minded as ever. Mairu and Kururi aren't my siblings, they're just to people convinced they are." "Bullshit!" "Don't scream what you are Shizu-chan. I'm leaving now so chill, kay?" Izaya smirked at Shizuo as he reached a hand out, "Un, deux, trois!" He snapped his fingers and a gate appeared. "What the fuck is that, Izaya?" Shizuo asked, to confused with the scene in front of him to be as pissed as before. "Really wanna know? Ask Celty about Gehenna and tell her Izaya told you to ask." Izaya laughed as he jumped in the gate. Shizuo reached a hand out to yank Izaya back but the gate slammed shut before Shizuo could even look inside. "IZAYA!" Shizuo stormed off until he was at Shinra's apartment. It took Shinra almost a minute before he answered the door, "Oh, hi Shizuo." "Hey. Is Celty here?" Shinra nodded, "Come on in." Shinra lead Shizuo inside the house where he told him to wait on the couch. He sat there for another minute or so before Celty walked in, "Hey Shizuo. What's up?" "Izaya. Bastard fucking disappeared into some gate then said if I wanted to know that I had to ask you about Gehenna gate." Celty's shoulders visibly tensed, "Izaya… Gehenna. Shizuo, there are things beyond this world out there. Izaya was one of them." "Huh?" Shizuo re-read her PDA, "So you expect me to believe Izaya was some demon or something?" "Yeah. I have no reason to lie to you, Shizuo. Besides he isn't just a demon try Satan's third youngest son. He has seven children total his youngest two are only half demon but his second youngest has no traits of a demon at all since the last two were twins… It's hard to explain. Just be glad the demon's gone, he's the real monster Shizuo. I feel bad for wherever he went." **Assiah** ~

A man walked through town, his very look made the average human get the chills. Surely this man was human but his nails were long and black, his skin white, his eyes red, and his ears were pointed. "So you're finally back, brother." The man walking stopped and turned on his heel, "It's only been 23 years. Miss me that much… Mephisto Pheles." The chairman of True Cross Academy laughed, "Of course, Izaya. 23 years is a fourth or so of human life." "And when you live forever?" "I guess it's not really important. So did you finally get bored of the human world?" Izaya laughed and spun on his heel to face his older brother, "I've been bored of it for a while, the one person who kept me there finally got boring and you should know what I do when I'm bored." Izaya got his switchblade out but before he could open the blade Mephisto Pheles set his hand on Izaya's, "Don't take your boredom out here, in fact our brother may interest you." "I assume you're talking about Rin. Humans bore me and I'm sick of my other brothers." "I assure you Rin's something else." Izaya laughed and put away his blade, "Fine." Izaya tapped his foot and looked around suspiciously, "How are the exorcist now a days?" "I'm sure you can handle them. Oh and if you want to start something with him steal that katana of his. It holds his powers." "Like my switchblade?" "I guess. It holds his powers though you just do it for the hell of it, right?" Izaya smirked and did a slight nod, "Good to see you still remember me well. Now to bug Rin~" Rin was sitting on the roof of True Cross, just enjoying the Sun… "So you're Rin?" He opened his eyes he hadn't even realised were closed until he heard the unfamiliar voice. "Who are you?" "I'm Izaya Orihara. An older brother of yours… You are Satan's son right? Anyways I'll assume you're a demon since you've got a tail and pointy ears. Oh! You also have the sword I was told about. So Rin…" Izaya smiled at Rin who now stood up, "I wanna see your flames." "No." "Come on I'll show you mine." Rin glared at Izaya, "Fine. You first." Izaya nodded and whipped out a switchblade. His smirk never faded as it flung open and his body was wrapped in what looked like normal flames, not blue. "Those aren't Satan's flames." "I'm sorry, when did the Demon, who may I remind you only knew about demons for a year, become a genius about demons?" Rin opened his mouth to speak only to be cut off, "Never. Anyways I've been in a… different area as of late and haven't seen a real demon for a long while, I've evolved from running… I mean fighting a certain someone. My flames are red and I've got a real fighting technique unlike your random attack style which I can predict thanks to Shizu-chan… No one you know." "Do you ever shut up?" Izaya shut his blade and smiled evilly at Rin. "Little boy, I'm an ancient demon who was an information broker in Ikebukuro and Shinjuku for 9 years. I say everything important and everything irrelevant will never be mentioned until I and no one else feels the need to say it." Izaya walked closer to Rin, "So are you going to hold up your half of the deal?" Rin made no movements besides walking back the same distance Izaya walked forward. Than for a fraction of a second Izaya's smirk grew and his hand flinched, by time Rin realised what happened he felt something slip from his shoulders. He looked down and seen only the black strap the connected his Katana's bag… His vision snapped back to Izaya to see him holding the bag, "Give that back!" "Oh?" Izaya removed the red bag and threw it at Rin, "Don't know what you'll do with it now though… You can also take this." He removed the swords sheath and threw the sword at Rin. Rin just looked at Izaya half shocked the other half pissed. "What? I can't fight you if you don't have your sword. Especially if I use mine!" Izaya looked around uneasily for a second, "But let's not fight here… Follow me." Izaya jumped off the roof and ran towards the forest, Rin chasing him. 'Still not as fun as with Shizu-chan. Nothing's even being thrown at me.' Once they were deep enough in the forest Izaya turned around suddenly and went to slice through Rin's chest like he did when he first met Shizuo. He moved though, "So you at least know how to dodge. That means I don't have to go easy on you!" Izaya's body lite on fire too, "Alright Rin, I've been itching for a fight that actually hurts for 23 years! Come at me!"

 **Ikebukuro ~** "Are you serious!?" "Yeah. That flea isn't getting away! So can you do it?" Celty put her fingers to her PDA and hesitantly typed, "Yeah I can send you to where Izaya is… I can't get you back though. This is our chance to never see Izaya again since we all hate him, we like you though so-" Shizuo looked away after that, "Listen, I'm also a monster so they'll be no issue. Two monsters gone in one day." Celty nodded her helmet, "Alright Shizuo. I really don't want to though. Before I send you, you need to know I'm not opening a gate but sending you wherever Izaya is… If he's in Gehenna now you'd die." Shizuo shrugged, "I'll be fine Celty." Celty stood up and did exactly what Shizuo asked… "Send me to Izaya." **Assiah ~** **The** two demons fought, the one laughing like a maniac the other shouting before his every attack. "Rin, screaming makes your attacks awfully easy to detect it's almost… laughable?" Izaya said the last word sincerely but it was what he was seeing behind Rin that made him sound questionable. "Shizuo!?" "Flea!" Izaya held his blade tighter, "How the Hell'd you get here?" "Celty. Now, what the Hell did you do to your look?! Oh and I have more questions for you!" Izaya rolled his eyes, "Can it wait? I'm kinda testing out my younger brother… well half brother, we have a different mother." Shizuo looked at the two of them closer, "Why are you two on fire and what's with the tails?" "Oh my God, Shizuo!" He turned to Rin and threw him his sheath, "Go do something else kid." Izaya turned back to Shizuo, not even caring if he was still there to listen, "These are Satan's flames, idiot! And the tails are just there okay!? You don't need to know anything else about them-" "Actually a demon's tail is it's weakness." "Rin, you moron!" He was about to kill Rin if he was pulled back by his tail, "Ow! Shizuo! Let me kill that bastard!" Shizuo laughed which made Izaya, for once in his life, confused. "What's so funny?" "You're actually angry. I don't think I've ever seen you this way." Izaya's fire simmered, he'd normally ask how he could stand his fire but it was Shizuo. "Well yeah, in case Celty forgot to tell you, I'm one of Satan's children." "Alright, fine. I just have one question for you now, why'd you leave? I mean I thought-" Izaya looked away, "Shizuo… I mean… that's why I left. Just look at me." "Are you fucking serious!? I don't care if you're a demon!" "I do! You'll die, Shizuo, and I won't unless an exorcist kills me! I left so I could forget about you, you idiot!" Izaya did a turn around to run away but came face to face with a man dressed as an… exorcist! Izaya ran behind Shizuo, "Shizuo's a human, you wouldn't hurt him." "Oi, flea what's your problem?!" "Exorcists Shizuo! That man is my problem because he's an exorcist!" "Then I'll kick his ass for you." Shizuo ran at the exorcists, the exorcist made no moves to hurt Shizuo unlike Shizuo who was focused on at least knocking this guy out. "Listen he's a demon, sir. He isn't allowed to live in Assiah unless special permission is granted." "Listen, exorcist. I'm not gonna hurt anyone I like humans too much to do that." The exorcist loaded a gun and pointed it at Izaya, "Then why'd you attack my brother?" "Wait, you're Yukio? You look nothing like Rin, aren't you twins?" He never lowered the gun even as he evaded Shizuo's attacks. "How do you know about us?" Izaya sighed, "Shizuo stop." Shizuo stopped attacking and went back to block Izaya. "I'm a brother of yours. I'm Satan's third youngest son. Let's say I wasn't trying to kill Rin, I was just curious to know how strong he was. I did the same thing with Shizuo here when I first met him." "It's still my job to get rid of you." "Harsh. Your own brother too, I'd hate to see how you treated Rin. You probably also pointed a gun at him." Yukio flinched for a minute, "Oh my God, you did too! I thought my fake siblings back in Ikebukuro were bad! Anyways this leads to my next move…" He grabbed Shizuo's hand and ran, "Hey Shizuo, this was fun but I think I actually like Ikebukuro better." "Huh?" "I'm saying we should he'd back. I mean sure I have no one there since you probably hate me know but you've got your friends and your brother." "I don't hate you, you flea. You piss me off really easy and yeah I'm really pissed that you left me but once you explained why… I mean that very small journey actually explains a lot about you." They both laughed as they ran still trying to get away from Yukio, "But Izaya." "What?" "If you call me monster still I'll start calling you demon." "Haha, fair enough Shizu-chan… Here!" He yanked Shizuo down an alley, Yukio running past it. "Brings back memories, huh Shizu-chan?" Shizuo laughed and nodded, "Un, deux, trois!" The snapped his fingers and a gate opened, "After you, monster~" "Same time, demon." Izaya rolled his eyes as Shizuo grabbed his hand and they walked the gate.

A.N: Well that was chapter 1, review if you want more. I don't have a real direction for this story so let me know if you want real Shizaya and not the shit I wrote before, more blue exorcist, or if I suck and shouldn't post new stories. I also know Izaya was a little out of character in Assiah but that's because Satan's presence is more 'there' and it just made him more evil… I have no excuse for Shizuo, I just need to try harder. If this gets popular I'll try to post every week! So long~


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